/* -*- c-basic-offset: 8 -*-
 rdesktop: A Remote Desktop Protocol client.
 Protocol services - ISO layer
 Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 1999-2008
 Copyright 2005-2011 Peter Astrand <astrand@cendio.se> for Cendio AB

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <iso.h>
#include <tcp.h>
#include <string.h>

/* Send a self-contained ISO PDU */
static void iso_send_msg(uint8 code) {
	STREAM s;

	s = tcp_init(11);

	out_uint8(s, 3); /* version */
	out_uint8(s, 0); /* reserved */
	out_uint16_be(s, 11); /* length */

	out_uint8(s, 6); /* hdrlen */
	out_uint8(s, code);
	out_uint16(s, 0); /* dst_ref */
	out_uint16(s, 0); /* src_ref */
	out_uint8(s, 0); /* class */

	s_mark_end(s);
	tcp_send(s);
}

static void iso_send_connection_request(char *username) {
	STREAM s;
	int length = 30 + strlen(username);

	s = tcp_init(length);

	out_uint8(s, 3); /* version */
	out_uint8(s, 0); /* reserved */
	out_uint16_be(s, length); /* length */

	out_uint8(s, length - 5); /* hdrlen */
	out_uint8(s, ISO_PDU_CR);
	out_uint16(s, 0); /* dst_ref */
	out_uint16(s, 0); /* src_ref */
	out_uint8(s, 0); /* class */

	out_uint8p(s, "Cookie: mstshash=", strlen("Cookie: mstshash="));
	out_uint8p(s, username, strlen(username));

	out_uint8(s, 0x0d); /* Unknown */
	out_uint8(s, 0x0a); /* Unknown */

	s_mark_end(s);
	tcp_send(s);
}

/* Receive a message on the ISO layer, return code */
static STREAM iso_recv_msg(uint8 * code, uint8 * rdpver) {
	STREAM s;
	uint16 length;
	uint8 version;
	s = tcp_recv(NULL, 4);
	if (s == NULL)
		return NULL;
	in_uint8(s, version);
	if (rdpver != NULL)
		*rdpver = version;
	if (version == 3) {
		in_uint8s(s, 1); /* pad */
		in_uint16_be(s, length);
	} else {
		in_uint8(s, length);
		if (length & 0x80) {
			length &= ~0x80;
			next_be(s, length);
		}
	}
	if (length < 4) {
		error("Bad packet header\n");
		return NULL;
	}
	s = tcp_recv(s, length - 4);
	if (s == NULL)
		return NULL;
	if (version != 3)
		return s;
	in_uint8s(s, 1); /* hdrlen */
	in_uint8(s, *code);
	if (*code == ISO_PDU_DT) {
		in_uint8s(s, 1); /* eot */
		return s;
	}
	in_uint8s(s, 5); /* dst_ref, src_ref, class */
	return s;
}

/* Initialise ISO transport data packet */
STREAM iso_init(int length) {
	STREAM s;

	s = tcp_init(length + 7);
	s_push_layer(s, iso_hdr, 7);

	return s;
}

/* Send an ISO data PDU */
void iso_send(STREAM s) {
	uint16 length;

	s_pop_layer(s, iso_hdr);
	length = s->end - s->p;

	out_uint8(s, 3); /* version */
	out_uint8(s, 0); /* reserved */
	out_uint16_be(s, length);

	out_uint8(s, 2); /* hdrlen */
	out_uint8(s, ISO_PDU_DT); /* code */
	out_uint8(s, 0x80); /* eot */

	tcp_send(s);
}

/* Receive ISO transport data packet */
STREAM iso_recv(uint8 * rdpver) {
	STREAM s;
	uint8 code = 0;
	s = iso_recv_msg(&code, rdpver);
	if (s == NULL)
		return NULL;
	if (rdpver != NULL)
		if (*rdpver != 3)
			return s;
	if (code != ISO_PDU_DT) {
		error("expected DT, got 0x%x\n", code);
		return NULL;
	}
	return s;
}

/* Establish a connection up to the ISO layer */
RD_BOOL iso_connect(char *server, char *username, RD_BOOL reconnect) {
	uint8 code = 0;

	if (!tcp_connect(server))
		return False;

	if (reconnect) {
		iso_send_msg(ISO_PDU_CR);
	} else {
		iso_send_connection_request(username);
	}

	if (iso_recv_msg(&code, NULL) == NULL)
		return False;

	if (code != ISO_PDU_CC) {
		error("expected CC, got 0x%x\n", code);
		tcp_disconnect();
		return False;
	}

	return True;
}

/* Disconnect from the ISO layer */
void iso_disconnect(void) {
	iso_send_msg(ISO_PDU_DR);
	tcp_disconnect();
}

/* reset the state to support reconnecting */
void iso_reset_state(void) {
	tcp_reset_state();
}
